Converter transformer winding stress analysis method, device and equipment and storage medium

Abstract

The invention discloses a converter transformer winding stress analysis method, which is applied to a single-phase four-column converter transformer, and comprises the following steps: obtaining the magnetic flux of a magnetic circuit adjacent to a main column of the converter transformer; determining a two-dimensional model of the main column according to the magnetic flux; inputting excitation current into the two-dimensional model, and determining a magnetic field model of the main column; the excitation current comprises a fundamental current and a harmonic current; characteristic parameters of the converter transformer are obtained, a vibration equation of the converter transformer is determined according to the characteristic parameters and the magnetic field model, and the vibration equation is used for expressing stress of a winding of the converter transformer. According to the method, the fundamental current and the harmonic current are combined to analyze the stress of the winding of the converter transformer, the vibration problem of the converter transformer in actual operation is deeply and systematically known, and sufficient theoretical basis and technical support are better provided for design optimization, performance improvement and fault prevention of the transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer stress analysis, and in particular to a converter transformer winding stress analysis method, device, equipment and storage medium. Background Art

[0002] As the efficiency and performance requirements of power systems and electrical equipment continue to increase, the application of UHV converter transformers in power systems has become more and more extensive. At the same time, the presence of harmonic currents poses a challenge to the safe and stable operation of UHV converter transformers, especially the winding part of the converter transformer, which may vibrate excessively under the action of harmonic currents, thus affecting its performance and life. At present, the research on the stress vibration of UHV converter transformer windings is mainly focused on the macro level, lacking a refined analysis of detailed changes; especially under the influence of complex harmonic current conditions. This has led to a lack of in-depth and systematic understanding of the vibration problems faced by UHV converter transformers in actual operation, and it is impossible to provide sufficient theoretical basis and technical support for the design optimization, performance improvement and fault prevention of transformers. Summary of the invention

[0003] Based on this, it is necessary to propose a converter transformer winding stress analysis method, device, equipment and storage medium to address the above problems.

[0004] A method for analyzing the stress of a converter transformer winding is applied to a single-phase four-column converter transformer, and the method comprises:

[0005] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0006] determining a two-dimensional model of the main column according to the magnetic flux;

[0007] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0008] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0009] In one embodiment, obtaining the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer comprises:

[0010] Obtaining the magnetomotive force and magnetic resistance of each magnetic circuit in the converter transformer;

[0011] The magnetic flux of each magnetic circuit is determined based on the magnetomotive force and the magnetic resistance.

[0012] In one embodiment, the magnetic resistance of each magnetic circuit in the converter transformer is obtained by the following steps:

[0013] Obtaining the magnetic permeability, magnetic circuit cross-sectional area and magnetic circuit length of each magnetic circuit in the converter transformer;

[0014] The magnetic resistance of each magnetic path is determined based on the magnetic permeability, the cross-sectional area of ​​the magnetic path and the length of the magnetic path.

[0015] In one embodiment, the magnetic resistance of each magnetic circuit is determined according to the magnetic permeability, the cross-sectional area of ​​the magnetic circuit and the length of the magnetic circuit by the following formula:

[0016]

[0017] Where R is magnetic resistance, d is magnetic path length, μ is magnetic permeability, and S is magnetic path cross-sectional area;

[0018] The magnetic flux of each magnetic circuit is determined according to the magnetomotive force and the magnetic resistance by the following formula:

[0019] ΦR=F

[0020] Among them, Φ is the magnetic flux, R is the magnetic resistance, and F is the magnetomotive force.

[0021] In one embodiment, the two-dimensional model of the main column is determined according to the magnetic flux by the following formula:

[0022]

[0023] Wherein, F is the magnetomotive force, Φ1 and Φ2 are the magnetic flux of the magnetic circuit adjacent to the main column, F' is the equivalent magnetomotive force, Φ'1 is the equivalent magnetic flux, R s ' um is the equivalent total magnetic resistance, R' m1 For R' m2 For R' m3 is the equivalent magnetic resistance of the magnetic circuit adjacent to the main column.

[0024] In one embodiment,

[0025] The excitation current expression is as follows:

[0026]

[0027] Wherein, i1 is the excitation current input to the grid-side winding of the main column, i2 is the excitation current input to the valve-side winding of the main column, I N1 is the fundamental current of the grid-side winding input to the main column, I k1 is the harmonic current input to the grid-side winding of the main column, I N2 is the fundamental current of the valve side winding input to the main column, I k2 is the harmonic current input to the valve side winding of the main column, IN is the rated current of the winding, t is the time, θ is the phase, α is the harmonic current content, and k is the harmonic current order;

[0028] The magnetic field model expression is as follows:

[0029]

[0030] Among them, J is the winding current density, S is the cross-sectional area of ​​the magnetic circuit, i is the excitation current, A is the vector magnetic potential, B is the magnetic induction intensity, V is the unit volume of the winding, and μ is the magnetic permeance.

[0031] In one embodiment, the vibration equation is expressed as follows:

[0032]

[0033] Among them, M is the winding mass matrix; C is the damping coefficient matrix; K is the stiffness coefficient matrix; F1 is the electromagnetic force of the grid-side winding of the transformer, F2 is the electromagnetic force of the valve-side winding of the transformer, and mg is the gravity; n is the winding current-leakage magnetic proportional coefficient, λ is the harmonic order, J1S is the harmonic current excitation amplitude of the grid-side winding of the transformer at the λth harmonic frequency, J is the winding current density in the magnetic field model, and S is the magnetic circuit cross-sectional area in the magnetic field model; J2S is the harmonic current excitation amplitude of the valve-side winding of the transformer at the λth harmonic frequency, and ω is the angular frequency.

[0034] A converter transformer winding stress analysis device, the device comprising:

[0035] An acquisition module, used to acquire the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0036] A first determination module, configured to determine a two-dimensional model of the main column according to the magnetic flux;

[0037] A second determination module is used to input an excitation current into the two-dimensional model and determine a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0038] The third determination module is used to obtain characteristic parameters of the converter transformer, and determine the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model.

[0039] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0040] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0041] determining a two-dimensional model of the main column according to the magnetic flux;

[0042] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0043] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0044] A computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the following steps:

[0045] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0046] determining a two-dimensional model of the main column according to the magnetic flux;

[0047] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0048] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0049] The converter transformer winding stress analysis method of the present invention is applied to a single-phase four-column converter transformer, including: obtaining the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer; determining the two-dimensional model of the main column according to the magnetic flux; inputting an excitation current into the two-dimensional model, and determining the magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current; obtaining characteristic parameters of the converter transformer, and determining the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress of the converter transformer winding. The present invention analyzes the stress of the converter transformer winding in combination with the fundamental current and the harmonic current, so as to achieve an in-depth and systematic understanding of the vibration problems of the converter transformer in actual operation, and better provide sufficient theoretical basis and technical support for the design optimization, performance improvement and fault prevention of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] in:

[0052] Figure 1 is an application environment diagram of a converter transformer winding stress analysis method in one embodiment;

[0053] Figure 2 is a flow chart of a converter transformer winding stress analysis method in one embodiment;

[0054] Figure 3 A schematic diagram of a two-dimensional model transformation process of a main column in one embodiment;

[0055] Figure 4 A converter transformer winding circuit model in one embodiment;

[0056] Figure 5 A schematic diagram of the distribution of winding magnetic flux density and magnetic lines of force at different harmonic current contents and different frequencies in one embodiment;

[0057] Figure 6 A schematic diagram of the change of the longitudinal leakage flux density with the main air channel height in one embodiment;

[0058] Figure 7 A schematic diagram of the change of the transverse leakage flux density with the main air channel height in one embodiment;

[0059] Figure 8 It is a schematic diagram of the change of the longitudinal leakage flux density with the main air channel height under the action of harmonic currents of different frequencies in one embodiment;

[0060] Fig. 9 It is a schematic diagram of the change of the transverse leakage flux density with the main air channel height under the action of harmonic currents of different frequencies in one embodiment;

[0061] Fig.10 A fitting image of valve-side winding temperature variation under different harmonic current frequencies in one embodiment;

[0062] Fig.11 A fitting image of valve-side winding temperature variation under different harmonic current frequencies in one embodiment;

[0063] Fig.12 is a structural block diagram of a converter transformer winding stress analysis device in one embodiment;

[0064] Fig.13 FIG. 4 is a structural block diagram of a computer device in one embodiment. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] As the efficiency and performance requirements of power systems and electrical equipment continue to increase, the application of UHV converter transformers in power systems has become more and more extensive. At the same time, the presence of harmonic currents poses a challenge to the safe and stable operation of UHV converter transformers, especially the winding part of the converter transformer, which may experience excessive vibration under the action of harmonic currents, thus affecting its performance and life. At present, the research on the stress vibration of UHV converter transformer windings is mainly focused on the macro level, lacking a refined analysis of detailed changes; especially under the influence of complex harmonic current conditions. This has led to a lack of in-depth and systematic understanding of the vibration problems faced by UHV converter transformers in actual operation, and is unable to provide sufficient theoretical basis and technical support for the design optimization, performance improvement and fault prevention of transformers. In order to solve the above-mentioned technical problems, the present application provides a converter transformer winding stress analysis method, which is applied to a single-phase four-column converter transformer, Figure 1 FIG. 1 is an application environment diagram of a converter transformer winding stress analysis method in an embodiment. Figure 1 , the converter transformer winding stress analysis method is applied to the converter transformer winding stress analysis system. The converter transformer winding stress analysis system includes a terminal 110 and a server 120. The terminal 110 and the server 120 are connected through a network, and the terminal 110 can be a desktop terminal or a mobile terminal, and the mobile terminal can be at least one of a mobile phone, a tablet computer, a laptop computer, etc. The server 120 can be implemented as an independent server or a server cluster composed of multiple servers. The terminal 110 is used to send the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer to the server, and the server 120 is used to determine the two-dimensional model of the main column according to the magnetic flux.

[0067] A method for analyzing the stress of converter transformer windings is applied to single-phase four-column converter transformers, such as Figure 2 As shown, the method includes:

[0068] Step 10: Obtaining the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0069] Specifically, in the present application, the converter transformer is an ultra-high voltage converter transformer. Taking a single-phase four-column ultra-high voltage converter transformer as an example, it has four magnetic columns, namely, a main column, a side column, a side yoke and a main yoke. The magnetic circuit calculation rule of Ohm's law is adopted. The present application calculates the magnetic flux of each magnetic circuit composed of the main column, the side column, the side yoke and the main yoke. Each adjacent magnetic column in the ultra-high voltage converter transformer constitutes a magnetic circuit, wherein the magnetic resistance of each magnetic column is determined based on the magnetic permeability of its material, the cross-sectional area of ​​the magnetic circuit and the length of the magnetic circuit. In addition, Kirchhoff's law of magnetic flux conservation and magnetic motive force balance is applied in the magnetic circuit, which corresponds to current conservation and voltage balance in circuit theory. Based on the above Ohm's law of magnetic circuit and Kirchhoff's law of magnetic circuit, the magnetic flux Φ1, Φ2, Φ3 of each branch in the magnetic circuit is obtained. By obtaining the magnetic motive force and magnetic resistance of each magnetic circuit in the converter transformer; and determining the magnetic flux of each magnetic circuit according to the magnetic motive force and the magnetic resistance. The magnetic resistance of each magnetic circuit is determined by the magnetic permeability, magnetic circuit cross-sectional area and magnetic circuit length of each magnetic circuit in the converter transformer. In this embodiment, the magnetic resistance of each magnetic circuit is obtained by the following formula:

[0070]

[0071] ΦR=F (2)

[0072] ∑Φ=Φ1+Φ2+Φ3=0 (3)

[0073] ∑Hl=∑NI (4)

[0074]

[0075] Where R is magnetic resistance, d is the length of the magnetic circuit, μ is the magnetic permeability, S is the cross-sectional area of ​​the magnetic circuit; Φ is the magnetic flux, R is the magnetic resistance, F is the magnetomotive force, Φ1, Φ2 and Φ3 are the magnetic flux of each magnetic circuit, R m1 , R m2 , R m3 and R m4 are the magnetic resistance of each magnetic column, H is the magnetic field intensity A / m on the magnetic circuit, l is the magnetic flux path, the unit is m, N is the number of winding turns, the unit is turns, I is the winding current, the unit is A, and the magnetic flux of the main column is obtained by combining the magnetic resistance, magnetic flux and magnetomotive force of each magnetic circuit.

[0076] Step 20: determining a two-dimensional model of the main column according to the magnetic flux;

[0077] Specifically, in order to establish a two-dimensional fine simulation model of the UHV converter transformer, such as Figure 3The figure shows the transformation process of the two-dimensional model of the main column, and the equivalent magnetic network method is used to convert the UHV converter transformer into a two-dimensional structure. In the equivalent magnetic network method, the consistency of the main column magnetomotive force F, magnetic resistance R, and magnetic flux Φ before and after the equivalent is ensured. By adjusting the magnetic resistance R and magnetic flux Φ of each part, the total magnetic resistance R of the main column is ensured. 总 and total magnetic flux Φ 总 This transformation ensures the equivalence of the main column magnetic resistance, from the original R m1 , R m2 , R m3 to R' m1 , R' m2 , R' m3 The main column magnetic flux is changed from the original Φ1 to Φ'1, so as to reflect the magnetic field distribution in the actual physical process and simplify the complexity of the model. The two-dimensional model of the main column is realized by the following formula:

[0078]

[0079] Wherein, F is the magnetomotive force, Φ1 and Φ2 are the magnetic flux of the magnetic circuit adjacent to the main column, F' is the equivalent magnetomotive force, Φ'1 is the equivalent magnetic flux, R s ' um is the equivalent total magnetic resistance, R' m1 For R' m2 For R' m3 is the equivalent magnetic resistance of the magnetic circuit adjacent to the main column.

[0080] Two-dimensional refined modeling is carried out based on the structure of the real UHV converter transformer winding. This application uses ZZDFPZ-405000 / 500-400 UHV converter transformer as the research object for simulation analysis. According to the structural parameters of the UHV converter transformer winding, refined modeling is carried out. The rated voltage of the grid-side winding of the UHV converter transformer is 530 / √3kV, the rated current is 2×662A, the inner diameter of the winding is 872.5mm, the outer diameter is 1002.5mm, and the winding height is 2294mm. The grid-side winding is divided into 8 areas from top to bottom by the oil baffle, which are named Area 1-Area 8 in sequence. Except for the bottom area containing 18 coils, each of the remaining areas contains 17 coils, totaling 137 coils, each coil contains 5 turns of coil, and each turn of coil is composed of 12 strands of wire in parallel. The horizontal oil channel width between the grid-side winding cakes is 3mm, and the vertical oil channel width between the winding and the partition is 10mm. The rated voltage of the valve side winding is 171.88 / √3kV, the rated current is 2×2041A, the inner radius of the winding is 1143mm, the outer radius is 1269mm, and the winding height is 2254mm. The valve side winding has 8 areas, named from top to bottom as Area 1 to Area 8. The bottom area contains 23 coils, and each of the remaining areas contains 25 coils, totaling 198 coils. Each coil is a turn, and each turn of the coil is composed of 56 strands of wire in parallel. The width of the horizontal oil channel between the valve side winding coils is 3mm, and the width of the vertical oil channel on the inner and outer diameter sides is different. The width of the oil channel on the inner diameter side is 16mm, and the width of the oil channel on the outer diameter side is 15mm. Finally, the core main column in the two-dimensional refined model is made the same as the three-dimensional true structure. The dimensions of the winding, core side column and iron yoke in the two-dimensional refined model are calculated according to the winding structure parameters. The calculation results of the equivalent core size are shown as follows: Figure 3 As shown in the figure, the equivalent iron core main column is 3300mm high and 1420mm in diameter, and the width of the iron core side column and the iron yoke is 150.51mm.

[0081] Table 1 Basic parameters of UHV converter transformer

[0082]

[0083] Step 30: Input an excitation current into the two-dimensional model and determine the magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current.

[0084] Specifically, Figure 4 As shown, the transient value of the two coil currents input to the main column, that is, the accurate solution of the excitation current, is realized through the circuit differential equation. The excitation current in this model includes the fundamental current and the harmonic current. The excitation current expression is as follows:

[0085]

[0086] Wherein, i1 is the excitation current input to the grid-side winding of the main column, i2 is the excitation current input to the valve-side winding of the main column, I N1 is the fundamental current of the grid-side winding input to the main column, I k1 is the harmonic current input to the grid-side winding of the main column, I N2 is the fundamental current of the valve side winding input to the main column, I k2 is the harmonic current input to the valve side winding of the main column, I N is the rated current of the winding, t is the time, θ is the phase, α is the harmonic current content, and k is the harmonic current order.

[0087] After solving the winding current density J based on the dynamic converter transformer winding model of current transient analysis, it is sequentially coupled to the magnetic field model. Under the influence of harmonics, it is the time-varying magnetic field of the transformer in the magnetic field. Assuming that the excitation current of the transformer at any time is known, the energy balance finite element method is used to calculate the magnetic vector potential A. On this basis, the magnetic induction intensity B at each point, the winding current density J, and the magnetic field model are obtained as follows:

[0088]

[0089] Among them, J is the winding current density, S is the cross-sectional area of ​​the magnetic circuit, i is the excitation current, A is the vector magnetic potential, B is the magnetic induction intensity, V is the unit volume of the winding, and μ is the magnetic permeance.

[0090] Step 40: Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0091] Specifically, the transient value of the leakage magnetic field is calculated by the above magnetic field model. The winding vibration of the UHV converter transformer is mainly generated by the electromagnetic force between the windings. Considering the voltage and current excitation characteristics during the operation of the UHV converter transformer, the axial vibration equations of the grid-side winding and the valve-side winding of the main column and the electromagnetic force they receive can be expressed by the following formulas:

[0092] Grid side winding:

[0093]

[0094] Valve side winding:

[0095]

[0096] Among them, M is the winding mass matrix; C is the damping coefficient matrix; K is the stiffness coefficient matrix; F1 is the electromagnetic force of the grid-side winding of the transformer, F2 is the electromagnetic force of the valve-side winding of the transformer, and mg is the gravity; n is the winding current-leakage magnetic proportional coefficient, λ is the harmonic order, J1S is the harmonic current excitation amplitude of the grid-side winding of the transformer at the λth harmonic frequency, J is the winding current density in the magnetic field model, and S is the magnetic circuit cross-sectional area in the magnetic field model; J2S is the harmonic current excitation amplitude of the valve-side winding of the transformer at the λth harmonic frequency, and ω is the angular frequency. The converter transformer winding stress analysis method of the present invention is applied to a single-phase four-column converter transformer, including: obtaining the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer; determining the two-dimensional model of the main column according to the magnetic flux; inputting the excitation current into the two-dimensional model, and determining the magnetic field model of the main column; the excitation current includes fundamental current and harmonic current; obtaining the characteristic parameters of the converter transformer, and determining the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, and the vibration equation is used to express the stress of the converter transformer winding. The present invention analyzes the stress of the converter transformer winding in combination with the fundamental current and the harmonic current, so as to achieve an in-depth and systematic understanding of the vibration problem of the converter transformer in actual operation, and can also analyze some stress conditions of the transformer, so as to better improve the transformer and provide sufficient theoretical basis and technical support for the design optimization, performance improvement and fault prevention of the transformer.

[0097] Finally, under the condition that the effective value of the transformer rated current remains unchanged, Figure 5 As shown, this application simulates and analyzes the distribution of magnetic flux density and loss distribution characteristics of windings under the action of harmonic current contents of 0%, 5%, 10%, 15%, 20% and frequencies of 50Hz, 250Hz, 350Hz, 550Hz and 650Hz, respectively, (a) magnetic flux density distribution and magnetic line distribution under rated current; (b) magnetic flux density distribution and magnetic line distribution under the action of 650Hz harmonic current with different harmonic current contents; (c) magnetic flux density distribution of windings under different harmonic frequencies with 20% harmonic current content. Based on the principle of unique variables, the simulation ensures that the total load rate after the superposition of harmonic current and fundamental current is always the rated load rate. The magnetic flux density distribution of the grid-side winding and the valve-side winding under different component harmonic currents is shown in the figure. Figure 5 The area between the grid-side and valve-side windings is the main magnetic flux leakage channel, called the main air channel. The maximum magnetic flux leakage is in the middle of the winding, with an intensity of 0.24T. The magnetic flux leakage intensity gradually decreases in the vertical direction, and the magnetic flux leakage density decreases to about 0.1T at the upper and lower ends of the winding. Figure 5 (a) The UHV converter transformer winding L 12 As the reference line, the winding leakage magnetic distribution under the action of harmonic currents of different amplitudes calculated on the reference line is obtained as follows Figure 3As shown in the figure, with the increase of harmonic current content, the maximum values ​​of axial and radial leakage flux of the winding increase. Figure 6 It is a trend diagram of the change of lateral leakage flux with height. The maximum lateral leakage flux of the winding appears at the two ends of the winding, and the maximum leakage flux directions of the upper and lower ends are opposite. Figure 7 This is a trend diagram of longitudinal magnetic flux leakage with height. The closer to the end of the winding, the smaller the longitudinal magnetic flux leakage is. The longitudinal magnetic flux leakage is the largest in the middle of the winding. At the same time, the winding leakage magnetic distribution under the action of harmonic currents of different frequencies calculated on the reference line is obtained as follows: Figure 8 and 9 As shown, the magnetic flux density of the winding does not change significantly under the action of harmonic currents of different frequencies, and the axial leakage flux distribution of the winding is large at both ends and small in the middle; the radial leakage flux distribution of the winding is large in the middle and small at both ends.

[0098] Based on the above, the calculation results of the electric-magnetic-thermal physical field are sequentially coupled to the solid force field through the data link, and the harmonic current excitation is set for the valve side winding, so that the total load rate after the superposition of the harmonic current and the fundamental current at the valve side is always the rated load rate. The simulation analysis of the winding force distribution characteristics under the action of harmonic current content of 0%, 5%, 10%, 15%, 20% and frequencies of 50Hz, 250Hz, 350Hz, 550Hz, and 650Hz is carried out, such as Fig.10 As shown in the figure, the winding force distribution diagram shows that, taking the valve side winding force as an example, the valve side winding stress is mainly concentrated in the upper and lower ends, and the middle part of the winding is more evenly stressed.

[0099] The stress distribution of the transformer valve side winding under the action of different harmonic current components is shown in the figure. Fig.11 As shown in the figure, with the increase of harmonic current content, taking the harmonic current frequency of 650Hz as an example, the average stress value of the valve side winding gradually increases from 240570N·m 2 Increased to 250970N·m 2 The increase was 4.32%; the maximum stress value increased from 3289630N·m 2 Increased to 4414350N·m 2 The increase is 34.19%. With the increase of the frequency of superimposed harmonic current, taking 20% ​​harmonic current content as an example, the average stress value of the valve side winding remains basically unchanged, and the maximum stress value increases from 3720200N·m 2 Increased to 4414350N·m 2 The increase is 18.6%. It can be seen that when analyzing the stress on the winding, the uneven stress on the winding caused by different harmonic current contents is more significant.

[0100] A converter transformer winding stress analysis device, such as Fig.12 As shown, the device comprises:

[0101] An acquisition module 100, configured to acquire the magnetic flux of a magnetic circuit adjacent to a main column of the converter transformer;

[0102] A first determination module 200, configured to determine a two-dimensional model of the main column according to the magnetic flux;

[0103] The second determination module 300 is used to input an excitation current into the two-dimensional model and determine the magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0104] The third determination module 400 is used to obtain characteristic parameters of the converter transformer, and determine the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model.

[0105] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0106] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0107] determining a two-dimensional model of the main column according to the magnetic flux;

[0108] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0109] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0110] A computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the following steps:

[0111] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0112] determining a two-dimensional model of the main column according to the magnetic flux;

[0113] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0114] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0115] Fig.13FIG. 1 shows an internal structure diagram of a computer device in an embodiment. The computer device may be a terminal or a server. Fig.13 As shown, the computer device includes a processor, a memory and a network interface connected via a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor may implement an age recognition method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor may implement a converter transformer winding stress analysis method. Those skilled in the art will understand that Fig.13 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0116] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0117] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0118] determining a two-dimensional model of the main column according to the magnetic flux;

[0119] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0120] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0121] A computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the following steps:

[0122] Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer;

[0123] determining a two-dimensional model of the main column according to the magnetic flux;

[0124] Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current;

[0125] Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

[0126] The converter transformer winding stress analysis method of the present invention is applied to a single-phase four-column converter transformer, including: obtaining the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer; determining the two-dimensional model of the main column according to the magnetic flux; inputting the excitation current into the two-dimensional model, and determining the magnetic field model of the main column; the excitation current includes fundamental current and harmonic current; obtaining the characteristic parameters of the converter transformer, and determining the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, and the vibration equation is used to express the stress of the converter transformer winding. The present invention analyzes the stress of the converter transformer winding in combination with the fundamental current and the harmonic current, so as to achieve an in-depth and systematic understanding of the vibration problem of the converter transformer in actual operation, and can also analyze some stress conditions of the transformer, so as to better improve the transformer and provide sufficient theoretical basis and technical support for the design optimization, performance improvement and fault prevention of the transformer.

[0127] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0128] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for analyzing the stress of a converter transformer winding, applied to a single-phase four-column converter transformer, characterized in that: The method comprises: Acquiring the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer; determining a two-dimensional model of the main column according to the magnetic flux; Inputting an excitation current into the two-dimensional model and determining a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current; Acquire characteristic parameters of the converter transformer, and determine a vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model, wherein the vibration equation is used to express the stress on the converter transformer winding.

2. The method for analyzing the stress of converter transformer windings according to claim 1, characterized in that: The obtaining of the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer comprises: Obtaining the magnetomotive force and magnetic resistance of each magnetic circuit in the converter transformer; The magnetic flux of each magnetic circuit is determined based on the magnetomotive force and the magnetic resistance.

3. The converter transformer winding stress analysis method according to claim 2, characterized in that: The magnetic resistance of each magnetic circuit in the converter transformer is obtained by the following steps: Obtaining the magnetic permeability, magnetic circuit cross-sectional area and magnetic circuit length of each magnetic circuit in the converter transformer; The magnetic resistance of each magnetic path is determined based on the magnetic permeability, the cross-sectional area of ​​the magnetic path and the length of the magnetic path.

4. The converter transformer winding stress analysis method according to claim 3 is characterized in that: The magnetic resistance of each magnetic circuit is determined according to the magnetic permeability, the cross-sectional area of ​​the magnetic circuit and the length of the magnetic circuit by the following formula: Where R is magnetic resistance, d is magnetic path length, μ is magnetic permeability, and S is magnetic path cross-sectional area; The magnetic flux of each magnetic circuit is determined according to the magnetomotive force and the magnetic resistance by the following formula: ΦR=F Among them, Φ is the magnetic flux, R is the magnetic resistance, and F is the magnetomotive force.

5. The method for analyzing the stress of converter transformer windings according to claim 1, characterized in that: The two-dimensional model of the main column is determined according to the magnetic flux by the following formula: Wherein, F is the magnetomotive force, Φ1 and Φ2 are the magnetic flux of the magnetic circuit adjacent to the main column, F' is the equivalent magnetomotive force, Φ'1 is the equivalent magnetic flux, R s ' um is the equivalent total magnetic resistance, R' m1 For R' m2 For R' m3 is the equivalent magnetic resistance of the magnetic circuit adjacent to the main column.

6. The converter transformer winding stress analysis method according to claim 1, characterized in that: The excitation current expression is as follows: Wherein, i1 is the excitation current input to the grid-side winding of the main column, i2 is the excitation current input to the valve-side winding of the main column, I N1 is the fundamental current of the grid-side winding input to the main column, I k1 is the harmonic current input to the grid-side winding of the main column, I N2 is the fundamental current of the valve side winding input to the main column, I k2 is the harmonic current input to the valve side winding of the main column, I N is the rated current of the winding, t is the time, θ is the phase, α is the harmonic current content, and k is the harmonic current order; The magnetic field model expression is as follows: Among them, J is the winding current density, S is the cross-sectional area of ​​the magnetic circuit, i is the excitation current, A is the vector magnetic potential, B is the magnetic induction intensity, V is the unit volume of the winding, and μ is the magnetic permeance.

7. The method for analyzing the stress of converter transformer windings according to claim 1, characterized in that: The vibration equation is expressed as follows: Among them, M is the winding mass matrix; C is the damping coefficient matrix; K is the stiffness coefficient matrix; F1 is the electromagnetic force of the grid-side winding of the transformer, F2 is the electromagnetic force of the valve-side winding of the transformer, and mg is the gravity; n is the winding current-leakage magnetic proportional coefficient, λ is the harmonic order, J1S is the harmonic current excitation amplitude of the grid-side winding of the transformer at the λth harmonic frequency, J is the winding current density in the magnetic field model, and S is the magnetic circuit cross-sectional area in the magnetic field model; J2S is the harmonic current excitation amplitude of the valve-side winding of the transformer at the λth harmonic frequency, and ω is the angular frequency.

8. A converter transformer winding stress analysis device, characterized in that: The device comprises: An acquisition module, used to acquire the magnetic flux of the magnetic circuit adjacent to the main column of the converter transformer; A first determination module, configured to determine a two-dimensional model of the main column according to the magnetic flux; A second determination module is used to input an excitation current into the two-dimensional model and determine a magnetic field model of the main column; the excitation current includes a fundamental current and a harmonic current; The third determination module is used to obtain characteristic parameters of the converter transformer, and determine the vibration equation of the converter transformer according to the characteristic parameters and the magnetic field model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 7.

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